如何在 Qt 中使用 QSyntaxHighlighter class 在 QML TextEdit 上实现富文本逻辑？

Question

我的 QML 文件中有一个 TextEdit，我有一个 QSyntaxHighlighter C++ class。我想在 C++ class 中指定突出显示逻辑并将其应用于 TextEdit，但我不确定如何在 QML 对象和 C++ class 之间建立连接。你也可以提供一些示例代码吗？我找不到如何使用 Qt 文档实现它。

Answer 1

您可以使用 TextEdit::textDocument, which holds an instance of QQuickTextDocument，获得对可以传递给 QSyntaxHighlighter 构造函数的基础 QTextDocument 的访问权。

Answer 2

万一有人需要更详细的解释。首先，我在自定义 C++ class.

中创建了一个 Q_PROPERTY

Q_PROPERTY(QQuickTextDocument* mainTextEdit READ mainTextEdit WRITE setMainTextEdit NOTIFY mainTextEditChanged)

然后我将textEdit.textDocument分配给QML中的Q_PROPERTY。

customClass.mainTextEdit = textEdit.textDocument

然后我调用initHighlighter()（函数必须是Q_INVOKABLE) in my QML which calls the constructor of my highlighter class and passes it the text document of the textEdit。

void initHighlighter()
{
Highlighter *highlighter;
highlighter = new Highlighter(m_mainTextEdit->textDocument());
}

注意：自定义荧光笔class需要派生自QSyntaxHighlighter。

Answer 3

实施示例：

HighlightComponent.h

class HighlightComponent : public QObject
{
Q_OBJECT
    //@formatter:off
    Q_PROPERTY(QString text
                       READ getText
                       WRITE setText
                       NOTIFY textChanged)
    //@formatter:on
    using inherited = QObject;
public:
    explicit HighlightComponent(QObject* parent = nullptr);

    static void registerQmlType();

    const QString& getText()
    {
        return _text;
    }

    void setText(const QString& newText)
    {
        if (newText != _text)
        {
            _text = newText;
            emit textChanged();
        }
    }

    Q_INVOKABLE void onCompleted();

signals:
    void textChanged();

private:
    std::unique_ptr<QSyntaxHighlighter> _highlight;
    QString _text = "";
};

HighlightComponent.cpp

HighlightComponent::HighlightComponent(QObject* parent)
        : inherited(parent)
{
}

void HighlightComponent::onCompleted()
{
    auto property = parent()->property("textDocument");
    auto textDocument = property.value<QQuickTextDocument*>();
    auto document = textDocument->textDocument();
    //TODO init here your QSyntaxHighlighter
}

void HighlightComponent::registerQmlType()
{
    qmlRegisterType<HighlightComponent>("com.HighlightComponent", 1, 0, "HighlightComponent");
}

main.cpp

int main(int argc, char* argv[])
{
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;
    HighlightComponent::registerQmlType();

    engine.load(QUrl(QStringLiteral("qrc:/view/main.qml")));

    return app.exec();
}

示例 QML

TextArea {
    id: testTextArea
    text: testTextArea.text
    //inputMethodHints: Qt.ImhNoPredictiveText

    onTextChanged: {
        testTextArea.text = text
    }

    HighlightComponent {
        id: testTextArea
        Component.onCompleted: onCompleted()
    }
}

链接：

https://wiki.qt.io/How_to_Bind_a_QML_Property_to_a_C%2B%2B_Function

http://doc.qt.io/qt-5/qtqml-cppintegration-exposecppattributes.html

http://wiki.qt.io/Spell-Checking-with-Hunspell

http://doc.qt.io/qt-5/qtqml-cppintegration-interactqmlfromcpp.html

http://doc.qt.io/qt-5/qtwidgets-richtext-syntaxhighlighter-example.html

如何在 Qt 中使用 QSyntaxHighlighter class 在 QML TextEdit 上实现富文本逻辑？

How to implement rich text logic on QML TextEdit with QSyntaxHighlighter class in Qt?

c++

qt

qml

qtquick2